In the field of photography, various polymers are commonly used as mordants in order to prevent the transfer of dyes.
Polymer mordants are disclosed in U.S. Pat. Nos. 3,898,088, 3,958,995, and 4,131,469, West German Patent Application Disclosure 2,941, and JP-A-53 30328, and JP-A-56-17352 (the term "JP-A" as used herein means an "unexamined published Japanese patent application").
In heat-developable light-sensitive materials as described in JP-A-58-58543, and JP-A-58-79247, and Japanese Patent Application Nos. 58-149046 and 58-149047, polymer mordants are employed for fixing anionic dyes.
However, these polymeric mordants exhibit excellent dye mordanting properties, but prove to be extremely poor with regard to preserving the dyes thus mordanted in a stable form.
In particular, a photographic system comprising a dye mordanted by this type of mordant has another disadvantage. When irradiated with light from a fluorescent tube or sunlight, the mordanted dye is susceptible to chemical change or decomposition.
On the other hand, polymer mordants wherein the mordanted dye is insensitive to chemical change or decomposition by light are disclosed in British Patents 2,011,921, 2,056,101, and 2,093,041, U.S. Pat. Nos. 4,115,124, 4,273,853, and JP-A-60-118834, JP-A-60-128443, JP-A-60 122940, JP-A-60 122921, and JP-A-60-235134. However, these mordants leave much to be desired.
Further, a process which comprises filling a polymeric mordant dispersion with a hydrophobic low molecular compound having discoloration inhibiting properties is disclosed in JP-A-57-202539. In this process, a polymeric mordant is impregnated with a compound having a proper hydrophibicity to provide a certain discoloration inhibiting effect.
However, the amount of the discoloration inhibiting compound which can be incorporated into the mordant according to this process is limited. Thus, a mordant having a further improved discoloration inhibiting capability has been desired.
In impregnating a latex with a discoloration inhibiting compound according to the process of JP-A-57-202539, the discoloration inhibitor is structurally limited. Thus, development of an effective process for fixing a discoloration inhibitor in a mordant layer has been desired.